Talking machine



Jan. 24, 1933. R. HILGENBERG 1,395,126

" TALKING MACHINE Filed Sept. 11, 1929 2 Sheets-Sheet 1 III'IIIIII/IIIIIIII.

Jan. 24, 1933. R. HILGENBERG TALKING MACHINE Filed Sept. 11, 1929 2 Sheets-Sheet '2 Patented a... 24, 1933 UNITED STATES PATENT OFFICE ROBERT HILGENBERG, OF LEIPZIG-MARIENHOHE, GERMANY TALKING MACHINE Application filed September 11, 1929, Serial No. 391,934, and in Germany August 5, 1929.

My invention relates to talking machines, and particularly to the mechanism connecting the sound box with the sound arm. It is an object of my invention to provide means for preventing the needle at the sound boxfrom jumping the grooves of the record under shock.

To this end I balance the weight of all parts by which the-sound box is supported,

' and provide means not influenced by gravity for holding the needle in the grooves of the record.

When a talking machine is subjected to shocks while playing, for instance in a motor car, it often occurs that the needle jumps the grooves of the record, even with comparatively slight irregularities, in curves or the like, interrupting the operation of the machine, and causing damage to the record and the sound box. The cause of this is that the parts supporting the sound box are not completely balanced in any relative position.

According to my invention, the sound arm and the bracket, if any, supporting the sound arm, together with the sound box, are balanced throughout, so that torqfies resulting from inertia forces and tending to lift the needle out of the sound groove, will not occur. Means not influenced by gravity, generally a spring, is provided for holding the needle in the groove, and, in the balancing of the parts, the weight of the means should be considered. In the drawings ailixed to this specification and forming part thereof the balancing of various types of sound arms and brackets according to my invention is illustrated diagrammatically by way of example.

In thedrawings Fig. 1 is a plan view, and Fig. 2 is an elevation showing a balanced sound arm with a normal sound box, and a balanced bracket, on which the arm is supported,

, .Fig. 3 is an elevation of a sound arm hav- 5 ing a horizontal sound box of the electric type hinged thereto,

Fig. 4 is a plan view of a sound arm in which the horizontal and vertical axes about which the sound arm is fitted to rock and to rotate, respectively, are combined in a single structure, and only one balance weight is required, I

Fig. 5 is a section on the line 55 in Fig. 1, Fig. 6 is a partly sectional elevation of a sound arm in which the arm is free to rotate about a vertical axis without interference, and to move along this axis against the action of a spring.

Referring now to the drawings, and first to Figs. 1 and 2, 1 is a sound bracket which is 0 fitted to rotate about a vertical axis through the medium of a support 2 on the top plate 29 of the machine, 3 is an extension of the bracket 1 beyond its axis of rotation which may be weighted in any suitable manner, for instance, by a block of lead cast into it, 6 is a sleeve at the end of the sound bracket opposite its weighted extension 3, 5 is a sound arm which is fitted to rock about a horizontal axis in the sleeve 6, 4 is the sound box at one end of 7 the arm 5 with the needle 16, 7 is an extension of the sound arm beyond the sleeve 6, 8 is a weight at the end of the extension, 9 is a clip on the-bracket 1, and 10 is a spring extending from the clip to an arm 11 on the sound arm 5. 76 The weight at 3 is so determined as to balance all the parts on the side opposite the vertical axis about which the bracket 1 is fitted to rotate, including the spring 10, its clip 9 and its arm 11, and the weight 8 is so determined as to balance the sound box 4 and the sound arm 5. In this manner the system is balanced throughout, that is, to the elimination of any torques in vertical or horizontal direction. Obviously with such a system the needle 16 would not be held under any pressure in the grooves of the record, not shown, and therefore it is necessary to provide means for holding the needle in contact with the groove, preferably the spring 10.

Referring now to Fig. 3 this illustrates a horizontal sound box of the electric type 4 at one end of the sound arm 23. The arm is fitted to rock about a horizontal axis in a bearing 14, which in turn is adapted to rotate about a vertical axis in the support 2' on the top plate 29, as described, 18 is a weight on the extension 3 of the bracket 23, 20 is a sleeve at the end of the bracket opposite the extension 3 in which the box 4 is fitted to rock about 100 a horizontal axis, 19 is a balance weight for the box, and 9 and 10 are the bracket and spring described, by which the needle 16 is held in the grooves of the record plate.

Referring now to Figs. 4 and 5, the sound arm 23 supports at one end the sound box 4 with a needle 16, and at its other end is bent to the shape ofthe letter C with two parallel reaches 24 and 26, the reach 26 being at the end of a return bend and supported in a bearing 27 at the end of a vertical pipe 28 which is fitted to rotate in a support 2 and, if desired, to be displaced vertically therein. is a rib which is soldered or otherwise secured in the bend of the C-shaped portion of the sound arm 23 and acts like the weight 18, Fig. 3, to balance vertical and horizontal torques. The spring for holding the needle 16 in the grooves of the record plate is here designed as a spiral spring which is secured to a casing 31 on the bearing 27 at one end and to the end of the pipe 26 at the other end. The weight 25 is so determined that the center of gravity of the system including the spring 32 is in the horizontal axis of the bearing 26.

Referring now to Fig. 6, the sound arm 23 is here made with a curved bond 36 which extends vertically downwards through a hole in the top plate 29 andthe weight 25 is arranged at the bend. A spring casing 41 with a cover 43 is inserted in another hole of the top plate. 37 is a clip at the end of a hollow pin 38 having a flange 45 which is supported on the bottom of the casing 47 A spring 44 is inserted between the flange 45 and the cover 43 of the casing. The sound arm 23 is free to rotate about the vertical axis of the pin 38 and to move vertically in parallelwith the axis against the pressure of the spring 44. lhe pressure of the spring may be regulated by providing a set screw or any other adjusting means in the casing 41.

Any suitable means may be provided for transferring the sound to the trumpet, not shown, for instance through the pipe 28, Fig. 5, or through a flexible tube 40, Fig. 6, which is secured on the lower end 39 of the sound arm 23.

I wish it to be understood that I do not desire to be limited to the'exact details of construction shown and described for obvious modifications will occur to a person skilled in the art. I

In the claim aflixed to this specification no selection of any particular modification of the invention is intended to the exclusion of other modifications thereof not covered by this claim.

I claim A talking machine comprising a bracket adapted to rock about an axis, a sound arm mountedto rock about an axis at right angles to said first-mentioned axis at one end of said bracket, a balance weight at the opposite end of said bracket, a sound box at one end of said sound arm, a balance weight at the opposite end of. said sound arm, and resilient means connecting said sound arm and said bracket, and tending to hold the needle of said sound box in the groove of a. sound record.

In testimony whereof I aflix mysignature.

' ROBERT HILGENBERG.

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